Abstract:The sedimentation and concentration of the unclassified tailings is the core process of tailings paste backfilling. According to the physicochemical properties of unclassified tailings in Wushan Copper Mine，a flocculation sedimentation test was carried out to determine the type of flocculant，the preparation concentration of flocculant solution，the feed concentration of tailings slurry and the amount of flocculant added. The results show that the best type of flocculant is anionic polyacrylamide （APAM），the best preparation concentration of APAM flocculant with a relative molecular weight of 1×107 is 1‰，the best feed concentration and flocculant dosage for unclassified tailings in Wushan Copper Mine is 15% and 20 g/t. When the feed concentration is 15% and the amount of flocculant added is 20 g/t，the fastest settling speed reaches 1.451 cm/s.